RIO DEL MAR -- Douglas Bernard Kirby, a Rio del Mar resident for 24 years and an international expert in sexual health, died Saturday while climbing Cotopaxi Volcano in Quito, Ecuador.

An avid mountain climber since age 15, the 69-year-old died from a heart attack during a night hike. He was vacationing in South America with his family. His final words were, "Isn't life great?"

"It's hard. He was such a great man and a great father," said his wife Gail Kirby, who wasn't on the hike. "We're very saddened. It's a great loss for us, and we've never experienced anything like this before."

Kirby was an expert in the prevention of unintended teen pregnancies, as well as HIV and AIDS prevention. He recently visited Uganda, where he trained health professionals on strategies to reduce the spread of HIV and AIDS.

Kirby received his doctorate in sociology from UCLA in 1975. From 1977 to 1983, he worked as director of the Social Science Group for Mathtech Inc. in Washington. In the late 1970s, his group applied for a grant from the Center for Disease Control and Prevention to analyze U.S. sex education programs.

Despite originally working in military defense contracts, Kirby's passion for sexual health and education led him to continue making advances in the field. In recent years, he also helped conduct research for the World Health Organization, the U.S. Agency for International Development and the United Nations Educational, Scientific and Cultural Organization.

As much as Kirby was a career man, he always put family first, said Gail Kirby, a professor at Santa Clara University.

"He was very committed to his work and balancing it with family," Gail Kirby said. "He made a point so he could come home and walk down to the beach to watch a sunset."

The two met in a grocery store checkout line in Maryland 30 years ago. Gail Kirby said he continued to be loving and compassionate throughout their marriage.

"Every weekend, we'd always have a movie night so we could go on a date, even when the kids were little," Gail Kirby said.

Kirby was also an avid runner, said Steven Bignell, a local publisher for Journeyworks Publishing. The two met in 1978 while Kirby was researching at Mathtech.

"We ran every weekend Doug was in town for the last 12 years, and every time we ran, Doug would stand on the coast at some point, look out and say, 'Isn't this amazing? Don't we live in a beautiful place?'" Bignell said. "He had a sort of this wide-eyed wonderment about the world."

And although Kirby traveled the world and had a great impact on various countries, he always remained humble, said friend John Thompson.

"If you had him over for dinner and served him a bowl of Special K cereal, he'd be happy," Thompson said.

BORN: Oct. 9, 1943 in Walla Walla, Wash.DIED: Dec. 22, 2012 in Quito, EcuadorSURVIVORS: His wife of 29 years Gail Kirby; his children Cameron, 19 and Kathryn, 24; and his brother Rob.EDUCATION: Bachelor's degree from the University of Chicago and UC Berkeley, 1966; doctorate in sociology from UCLA, 1975CAREER: Senior research scientist, ETR AssociatesCOMMUNITY INVOLVEMENT: In addition to mountain climbing since age 15, Kirby enjoyed hang gliding and skydiving. He took his son Cameron skydiving for his 18th birthday; they landed at Beer Can Beach in Rio del Mar.SERVICES: 1 p.m. Jan 5 at the La Selva Beach Community Church, 26 Florido Ave., La Selva BeachCONTRIBUTIONS: Donations can be made to Zambia Orphans of AIDS at zambiaorphans.org

Editor's note: This story has been updated to clarify that Doug Kirby's family was not with him on his final hike, but had traveled with him to South America.